Methods and apparatus for moldings filling and sealing hollow thermoplastic containers are illustrated in U.S. Pat. No. 3,597,793 to Weiler et al. and U.S. Pat. No. 4,707,966 to Weiler et al.
Of particular interest is the method for forming and filling a container, of the type disclosed in U.S. Pat. No. 3,597,793, which container includes a frangible web to allow a closure to be severed and removed from the container.
The method disclosed therein initially includes the step of extruding a tubular parison between two coacting main mold halves. The main mold halves are then closed around the parison. A segment of the extruded parison is severed at a location extending out of the closed mold halves and the severed segment is held open by a pair of holding jaws.
Next, a blowing and filling nozzle assembly is moved downwardly into the parison opening and between two sealing mold halves. The nozzle assembly includes a mandrel which is urged against the parison wall. The container is then formed by blowing gas to extend the parison segment outwardly against the walls of the main mold halves.
Thereafter, liquid is introduced into the formed container through a fill nozzle. After the container has been filled, the blowing and filling nozzle assembly is retracted and the sealing mold halves are moved together pinching the exposed top portion of the parison segment to form a unitary closure for the container and delineated from the container by a frangible web.
After the container has been sealed at the top, the main mold halves and the separate upper sealing mold halves are opened and the finished container is removed.
Although the above-discussed apparatus and method for forming a container with a frangible web is satisfactory in many applications, it is not adapted for the application where it is desirable to form and mold not only a frangible web between the container and the closure of the container but also to provide locking lugs around the access opening for the container.
It would thus be desirable to provide an apparatus and method for simultaneously molding a frangible web between the container and its unitary closure as well as locking lugs for connecting the container to a dispensing system such as an intravenous kit. The present invention meets these needs.